Re: What Protocols for TDD are used in Holland and Switzerland?
- From: et472@xxxxxxxxxxxxxxxxxxx (Michael Black)
- Date: 23 Sep 2006 16:12:23 GMT
"Radium" (glucegen1@xxxxxxxxxx) writes:
Hi:Kid, you don't even grasp what TDD is about.
http://en.wikipedia.org/wiki/Telecommunications_devices_for_the_deaf
quote:
"The original standard used by TDDs is the Baudot code implemented
asynchronously at either 45.5 or 50 baud, 1 start bit, 5 data bits, and
1.5 stop bits. Baudot is a common protocol in the US. In Europe,
different states use different protocols. For example, V.21 is found in
the UK and several Scandinavian countries. Other protocols used for
text telephony are EDT, DTMF, V.23, etc."
Doesn't say anything about Holland or Switzerland. I've tried hard to
look for information regarding TDD protocols in Swizterland and
Holland. I've haven't found any.
What protocols for TDD are used in Switzerland and Holland?
It dates from the era of Teletype machines, big clunky and noisy.
They were available as surplus, and so some guy decided they'd be
useful as a means of communication over the phone for the deaf.
It was a 5bit baudot standard because that's what the machines
that could be had for nothing were.
The "modem" standards were influecned by amateur radio teletype
standards, though I don't know if TDD used the exact same standards.
Hence, the only way certain countries don't use 5bit baudot for
TDD is A)the standards have changed in recent years because it's
a lot easier to use a computer than find an old Teletype machine
(which wouldn't actually make it a standard) or B) some countries
never had TDD until long after the Teletype machine era, so they
implemented something different.
Michael
.
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